Monounsaturatedn-9 fatty acids and adipocyte lipolysis in rats

To investigate the role of the monounsaturatedn-9 fatty acids (MUFA) in the lipolytic activity of adipocytes, a study was carried out in which an increase in MUFA was produced in the tissues by two different methods; by the dietary enrichment of oleic acid or by producing an essential fatty acid deficiency syndrome. For this, forty-five male Sprague–Dawley rats were fed with a normal-energy diet and were subdivided into three groups. The diets varied in the type of dietary fat; palmitic acid, olive oil, or soyabean oil+palmitic acid. At the end of the study measurements were taken of weight, plasma leptin, tissue concentration of fatty acids, fat-cell size in the epididymal and the omental adipose tissues, adipocyte lipolytic activity of both tissues after stimulation with adrenaline, and the capacity of insulin to inhibit lipolysis. The baseline and adrenaline-stimulated lipolytic activity were greater and the anti-lipolytic capacity of insulin lower in the animals undergoing an increase in MUFA in the tissues (palmitic-acid and olive-oil diets). The area under the curve of glycerol, used as an indicator of lipolytic activity, was positively correlated with the concentration of MUFA and negatively with polyunsaturated fatty acids in the adipose tissues. It is concluded that an increase in tissue MUFA, however obtained, induces an increase in lipolytic activity.

Serum phospholipid fatty acid profile and dietary intake in an adult Mediterranean population with cystic fibrosis

The relative importance of the usual diet in serum phospholipids in subjects with cystic fibrosis (CF) has been poorly studied. To compare the fatty acid profile in serum phospholipids from adult CF subjects with that of healthy subjects, and determine the role of the normal diet in this profile, we studied thirty-seven adult CF subjects with stable pulmonary disease and thirty-seven healthy controls matched for age, sex and nutritional status. A dietary questionnaire was obtained, anthropometric data were recorded, and the fatty acid profile measured by GLC. Compared with the controls, the percentages of myristic, palmitoleic and stearic acids and total MUFA were significantly higher in the CF group, and DHA, linoleic acid, total PUFA and n−6 fatty acids were significantly lower in the CF group. The CF subjects with worse pulmonary function and with pancreatic insufficiency had significantly lower levels of linoleic and n−6 fatty acids. The total energy intake was significantly higher in the CF subjects, although the energy distribution in the CF subjects and the controls was not different for the carbohydrates, lipids and proteins. No differences were detected in fat intake for MUFA (51 (sd 4) v. 52 (sd 4) %) or saturated fatty acids (33·5 (sd 5) v. 31·2 (sd 3·8) %), but the PUFA were slightly lower in the CF subjects (15·4 (sd 4·5) v. 17·4 (sd 4·2) %; P=0·02). The usual dietary intake of fatty acids by adult CF subjects does not appear to explain the difference in the fatty acid profile compared with controls. This suggests an abnormal fatty acid metabolism in CF subjects.

Protection from inflammatory disease in insulin resistance: the role of mannan-binding lectin

AIMS/HYPOTHESIS

Decreased sensing of the innate immune system may lead to chronic activation of the inflammatory cascade. We hypothesised that mannan-binding lectin (MBL) deficiency may confer risk of obesity and insulin resistance.

MATERIALS AND METHODS

We performed a cross-sectional study of MBL protein concentration (n=434) and MBL2 gene mutations (exon 1) (n=759) in association with obesity, markers of inflammation and insulin action (euglycaemic clamp, n=113), and a longitudinal study of MBL protein before and after weight loss in obese patients (n=10). We also studied the effects of MBL in vitro in muscle cells and circulating MBL-A (mouse equivalent of human MBL) in a mouse model.

RESULTS

Among 434 consecutive non-diabetic men, the age-adjusted serum MBL concentration was lower in obese subjects than in lean subjects (median: 959 microg/ml [interquartile range: 116.8-2,044 microg/ml] vs 1,365 [467-2,513] microg/ml; p=0.01) and was accompanied by increased serum inflammatory markers. Insulin action correlated significantly with serum MBL (r=0.49, p<0.0001). Serum MBL concentration increased by a median of 110.2% after weight loss. The change in serum concentration of MBL was positively associated with the increase in insulin sensitivity (r=0.713, p=0.021). At least one MBL2 gene mutation was present in 48.2% of obese vs 39.3% of non-obese subjects (p=0.037). The plasma concentration of MBL-A was lower in insulin-resistant obese ob/ob mice, as was the glucose/insulin ratio. Incubation of rat soleus muscle with human MBL markedly increased fatty acid oxidation.

CONCLUSIONS/INTERPRETATION

These findings suggest that MBL, previously thought only to be involved in inflammation and immune system function, affects metabolic pathways.

Morbidly obese individuals with impaired fasting glucose have a specific pattern of insulin secretion and sensitivity: effect of weight loss after bariatric surgery

BACKGROUND

Obesity is often associated with hyper-secrection of insulin. Impaired fasting glucose (IFG) has recently been redefined as a fasting plasma glucose of 5.6-6.9 mmol/L. The aim of this study was to determine whether changes in insulin secretion in morbidly obese persons also commence with normal serum glucose levels.

METHODS

32 morbidly obese subjects were studied before and after bariatric surgery. Measurements were made of glucose tolerance (K(G)), insulin sensitivity (SI), first-phase insulin release and the disposition index (DI) from a frequently sampled intravenous glucose tolerance test.

RESULT

In morbidly obese subjects, the SI (P<0.01), DI (P<0.01) and first-phase insulin release (P<0.02) started changing with serum glucose levels considered to be normal (5.00-5.28 mmol/L). K(G) showed a clear slope according to the baseline glycemia status (P<0.05), and it was significantly related with the DI, both before (r=0.76, P<0.001) and after (r=0.57, P=0.002) surgery. Following surgery, all the variables significantly associated with insulin secretion and insulin sensitivity recovered significantly. The most significant changes occurred in morbidly obese individuals with IFG.

CONCLUSIONS

Morbidly obese subjects show slopes of insulin sensitivity and insulin secretion in accordance with their baseline serum glucose levels. The fall in first-phase insulin release begins when serum glucose values are considered normal. Morbidly obese persons with the IFG phenotype have a specific pattern of insulin sensitivity and insulin secretion. K(G) clearly discriminates the clinical phenotypes, depending on baseline serum glucose levels.

Pro12Ala polymorphism of the PPARG2 gene is associated with type 2 diabetes mellitus and peripheral insulin sensitivity in a population with a high intake of oleic acid

Activation of the PPAR gamma 2 gene (PPARG2) improves the action of insulin and its lipid metabolism. We examined the association between Pro12Ala polymorphism of PPARG2, type 2 diabetes mellitus (DM2), and peripheral insulin sensitivity in a population with a high intake of oleic acid. A cross-sectional, population-based study was undertaken in Pizarra, a small town in the province of Malaga in southern Spain. A total of 538 subjects, aged 18-65 y, were selected randomly from the municipal census. All subjects underwent a clinical, anthropometrical, and biochemical evaluation, including an oral glucose tolerance test and Pro12Ala polymorphism of PPARG2. Insulin resistance was measured by homeostasis model assessment. Those subjects with the Ala-12 allele had an odds ratio for impaired fasting glucose of 0.55, for impaired glucose tolerance of 0.59, and for DM2 of 0.30. The intake of monounsaturated fatty acids (MUFA) contributed to the variance of the homeostasis model assessment insulin resistance index (HOMA IR) (P = 0.04), with a 2-way interaction between the Ala-12 allele of PPARG2 and the intake of MUFA (P = 0.005). The results suggest the existence of an interaction between Pro12Ala polymorphism of PPARG2 and dietary MUFA, such that obese people with the Ala-12 allele have higher HOMA IR values, especially if their intake of MUFA is low.

Dietary fatty acids and insulin secretion: a population-based study

OBJECTIVE

Few epidemiological studies have examined the relationship of dietary fatty acids, especially MUFA, with the interrelation between insulin secretion and insulin resistance. We assessed the relation of dietary fatty acids with insulin secretion in a free-living population.

DESIGN AND SETTING

This cross-sectional, population-based study was undertaken in Pizarra, a small town in Spain.

SUBJECTS AND METHODS

Anthropometrical data were collected for 1226 persons selected randomly from the municipal census, 538 of whom (randomly chosen) were given a prospective, quantitative, 7-day nutritional questionnaire. The fatty acid composition of the serum phospholipids was used as a biological marker of the type of fat consumed. Beta-cell function (betaCFI) and insulin-resistance index (IRI) were estimated by the Homeostasis Model Assessment.

RESULTS

To determine which factors influence the variability of the betaCFI, we analyzed the variance of the betaCFI according to sex, the presence of carbohydrate metabolism disorders and the different components of the diet, adjusting the models for age, body mass index (BMI) and IRI. The dietary MUFA and polyunsaturated fatty acids (PUFA) contributed to the variability of the betaCFI, whereas only the proportion of serum phospholipid MUFA, but neither the saturated fatty acids nor the PUFA accounted for part of the variability of the betaCFI in a multiple regression analysis.

CONCLUSION

The results of this population-based study corroborate the results of other clinical and experimental studies suggesting a favorable relationship of MUFA with beta-cell insulin secretion.

SPONSORSHIP

Fondo de Investigación Sanitaria, Junta de Andalucía and the Asociación Maimónides.

Association between MspI polymorphism of the APO AI gene and Type 2 diabetes mellitus

AIMS

Genes of the Apo AI/CIII/AIV cluster on chromosome 11 have been related to plasma lipid patterns. The close relationship between carbohydrate metabolism and lipid metabolism warrants investigation of the association between this cluster and Type 2 diabetes mellitus. We therefore examined the possible association between polymorphisms of this cluster and Type 2 diabetes mellitus as part of a study of the prevalence of diabetes and the metabolic syndrome in southern Spain.

METHODS

A total of 1224 persons were selected randomly from the town of Pizarra in the province of Malaga, southern Spain. The sample errors for the prevalence of Type 2 diabetes mellitus and the three polymorphisms studied were all < or = 4%. All subjects underwent phenotyping after an oral glucose tolerance test (75 g) (WHO 1998 criteria) and the XmnI and MspI polymorphisms of Apo AI and the SstI polymorphism of Apo CIII were genotyped.

RESULTS

Those subjects with the mutated AA genotype of the MspI polymorphism (-75 G-->A) of Apo AI had a greater risk of impaired glucose tolerance [odds ratio (OR) = 1.95, CI = 1.02-3.8, P = 0.05], Type 2 diabetes mellitus, both known (OR = 7.38, CI = 1.3-39.7, P = 0.02) and unknown (OR = 3.7, CI = 1.4-9.9, P = 0.009). This risk was independent of age, sex, obesity, triglyceride level, HDL cholesterol and pattern of insulin resistance.

CONCLUSIONS

Pending confirmation in prospective studies, the AA genotype of the MspI polymorphism of the Apo AI gene, within the Apo A-I/C-III/A-IV cluster, seems to be a risk factor for Type 2 diabetes mellitus.

Response to a urate-lowering diet according to polymorphisms in the apolipoprotein AI-CIII-AIV cluster

OBJECTIVE

The apolipoprotein AI-CIII-AIV cluster has been associated with the response to a urate-lowering diet, and polymorphisms in the apolipoprotein CIII gene have been associated with hyperuricemia and hypertriglyceridemia. We assessed the influence of polymorphisms in the apolipoprotein AI-CIII-AIV cluster on the response to a urate-lowering diet in patients with hyperuricemia.

METHODS

A urate-lowering diet was followed for 2 weeks by 64 men with hyperuricemia. Plasma concentrations of triglycerides, cholesterol, glucose, and uric acid, and the uric acid clearance and 24-hour uric acid urinary excretory fraction were measured before and after the diet. The data were analyzed in association with the polymorphisms of the apolipoprotein AI-CIII-AIV gene cluster.

RESULTS

After the urate-lowering diet, the plasma levels of triglycerides, cholesterol, glucose, and uric acid and 24-hour uric acid excretion all fell significantly. Paired sample ANOVA showed that the decrease was mainly due to the diet, except for the plasma triglycerides, which were influenced by allele X2 of the XmnI polymorphism of the apolipoprotein AI gene.

CONCLUSION

The response of the biological variables to a urate-lowering diet was mainly influenced by diet. Changes in triglycerides were also influenced by the apolipoprotein AI XmnI polymorphism (p = 0.04), suggesting a gene-diet interaction (p = 0.03).

Influence of age and sex on levels of anti-oxidized LDL antibodies and anti-LDL immune complexes in the general population

Most studies of antibodies to oxidized LDL have been undertaken in patients with different diseases and cardiovascular risk factors. However, very few studies have researched the distribution and determining factors of antibodies to oxidized LDL in the general population. A total of 1,354 persons (817 females and 537 males) aged 5-65 years were included in this study. They were selected randomly from the population census of Málaga, in southern Spain. The females had lower levels of total cholesterol and triglycerides and higher levels of HDL-cholesterol and a very significant increase (P < 0.0001) in levels of anti-oxidized LDL [low density lipoprotein modified by malondialdehyde (MDA-LDL)] antibodies but no difference in levels of immune complexes consisting of LDL and IgG antibodies (anti-LDL immune complex). Younger persons (16-35 years) had higher levels of anti-oxidized LDL (MDA-LDL) antibodies than persons older than 35 years (P = 0.05). Levels of immune complexes were significantly higher (P = 0.05) in persons aged 5-15 years than in persons older than 40 years. A very weak association was found between levels of anti-oxidized LDL (MDA-LDL) antibodies and anti-LDL immune complexes. The higher prevalence of anti-oxidized LDL (MDA-LDL) antibodies in females and young persons is in agreement with studies that found an inverse association between atherosclerosis and the level of these antibodies.

Corona Glans Clitoroplasty and Urethropreputial Vestibuloplasty in Male-to-Female Transsexuals: The Vulval Aesthetic Refinement by the Andalusia Gender Team

For more than a decade the pedicled island neurovascular flap of the glans penis has been the standard procedure for clitoroplasty in intersex anomalies and in male-to-female genital sex reassignment surgery. Most authors focusing on genitoperineal reconstructions have used the island neurovascular flap of the dorsal shaft of the penis, including a variable-sized dorsal chip of the glans penis as the distal and functional portion of the flap. Although this dorsal glans clitoroplasty technique for neoclitoral reconstruction is well known, it nevertheless deserves scientific revision, with a view to improving several neglected aesthetic and functional points. The authors describe a new method for reconstruction of the neoclitoris in male-to-female transsexuals, the corona glans clitoroplasty. It is based on a modification of the original pedicled island neurovascular flap of the glans penis. The main difference compared with the dorsal glans clitoroplasty is that, distally, this method includes a bifid dorsolateral coronal flap designed in the shape of an open lotus flower or a bull's horns. Furthermore, a semicircular preputial flap is retained, attached to the bifid coronal flap of the glans, to improve the cosmetic appearance of the vestibulum and avoid growth of hair around the neoclitoris. Finally, a small dorsal flap of the spongiomucosa urethra designed in the shape of a pencil tip is added to improve the cosmetic appearance of the vestibulum between the neoclitoris and the urethral neomeatus. Since October of 1999, the authors have performed more than 30 genital sex reassignment surgeries in male-to-female transsexuals, of whom 16 underwent their technique of corona glans clitoroplasty. The authors describe and discuss the anatomic basis and clinical implications of this technique and its cosmetic and potential functional advantages. They also consider the anatomic differences among four distal designs of the pedicled island neurovascular flap of the glans penis: dorsal, lateral, ventral, and corona glans clitoroplasty in male-to-female transsexuals.

Dietary palmitic acid influences LDL-mediated lymphocyte proliferation differently to other mono- and polyunsaturated fatty acids in rats

Recent studies suggest that the biological effects of saturated fatty acids depend on the length of their chain. We compared the effect of diets containing different fatty acids on plasma lipids and lymphocyte proliferation in the presence of lovastatin and with increasing amounts of LDL. Lymphocytes from rats fed with a diet rich in palmitic acid had a greater lymphocyte proliferation capacity than those from rats fed with diets rich in oleic acid, linoleic acid, or fish oil. This effect was maintained when small amounts of polyunsaturatwed fatty acids (PUFA; sunflower oil) were added to the palmitic acid diet. LDL receptor activity, measured by the capacity of lovastatin to revert the inhibition of lymphocyte proliferation with increasing amounts of LDL in the medium, was greater in the rats fed with palmitic acid, and was similar to the other groups when small amounts of PUFA were added. All the groups had similar levels of plasma cholesterol, but the LDL levels were significantly lower in the group fed with palmitic acid plus PUFA. The highest HDL-cholesterol (HDLc) levels were found in the palmitic acid group and the lowest LDL-cholesterol (LDLc)/HDLc ratio in the palmitic acid plus PUFA group. These results suggest that diets rich in palmitic acid do not raise total cholesterol, but reduce LDLc or keep it normal, and raise HDLc levels. This effect may be partly due to an increase in LDL receptor activity. The inclusion of small amounts of PUFA in the diet rich in palmitic acid substantially modified the LDL receptor response in the lymphocytes, suggesting that the proportion of different families of dietary fatty acids may be more important than the individual amount of each in absolute terms to explain their effects on plasma lipids and lipoproteins.

Plasma levels of alpha-melanotropin and ACTH-like immunoreactivities do not vary by season or skin type in women from southern and central Europe

Melanotropins (MSH) are involved in tanning by stimulating melanocytes via the activation of the melanocortin-1 receptor to melanin production. Its main site of production is the pituitary gland, but alpha-MSH and related ACTH peptides are produced at other sites, including the skin. It has been hypothesized that systemic levels of alpha-MSH are controlled by a varying UV radiation (UVR) exposure. A seasonal rhythm of plasma levels has been proposed by some authors. We investigated healthy females in southern Spain and central Austria in summer and winter. The alpha-MSH and ACTH-like immunoreactivity plasma levels did not present marked differences between the groups of Malaga and Linz, dark and light skin and between seasons. An association of alpha-MSH to ACTH or cortisol levels could not be observed. Individual values of alpha-MSH were shown to be relatively constant at both times of measurement (p<0.05 by rank correlation) indicating an independent personal disposition for individual systemic alpha-MSH immunoreactivity levels. Our data do not support the concept of a marked involvement of melanotropins of pituitary origin in tanning, and no seasonal rhythm was observed.

Patterns of insulin resistance in the general population of southeast Spain

The aim of this study was to evaluate patterns of insulin resistance in the general population. The study was cross sectional. Clinical, anthropometric, and lipid measurements were made in 1226 persons aged 18-65 years. An oral glucose tolerance test (OGTT) was performed in 1020 subjects, with insulin levels determined at baseline and after 2 h. The homeostasis model assessment insulin resistance index (HOMA IR) and HOMA beta-cell function were calculated. Compared with subjects with normal glucose tolerance, the groups with abnormal OGTT had different baseline insulinemia, 2 h post OGTT insulinemia, HOMA IR and HOMA beta-cell indices. Serum insulin levels at baseline and 2 h after OGTT showed a characteristic pattern for each category of glucose tolerance, resulting from the different insulin responses. In the subjects with normal glucose tolerance, the pattern of the relationships between both types of serum insulin levels was exactly the same, so that it was possible to determine risk groups according to the ratio of baseline serum insulin/2 h insulin. HOMA IR and HOMA beta-cell were significantly associated with the risk of impaired fasting glucose, previously unknown diabetes mellitus, and known diabetes mellitus. These results support the rationale for introducing preventive measures against insulin resistance in the general population.

Intelligence quotient and iodine intake: a cross-sectional study in children

The association between iodine deficiency and poor mental and psychomotor development is known. However, most studies were undertaken in areas of very low iodine intake. We investigated whether a similar association is found in schoolchildren from southern Europe with a median urinary iodine output of 90 microg/liter. Urinary iodine levels were measured in 1221 children who also completed a questionnaire about their usual dietary habits. Intelligence quotient (IQ) was measured by Cattell's g factor test. IQ was significantly higher in children with urinary iodine levels above 100 microg/liter. The risk of having an IQ below the 25th percentile was significantly related to the intake of noniodized salt and drinking milk less than once a day. As expected, the risk of having an IQ below 70 was greater in children with urinary iodine levels less than 100 microg/liter. In conclusion, this study demonstrates that the IQ of schoolchildren in a developed country can be influenced by iodine intake. The results support the possibility of improving the IQ of many children from areas with mild iodine deficiency by ensuring an iodine intake sufficient to achieve a urinary iodine concentration greater than 100 microg/liter.

Oleic acid from cooking oils is associated with lower insulin resistance in the general population (Pizarra study)

AIM

To evaluate the relation between type of dietary fatty acid and degree of insulin resistance.

DESIGN

A cross-sectional study.

METHODS

Anthropometrical data were measured in 538 subjects, aged 18-65 Years, selected randomly from the municipal census of Pizarra (Spain). An oral glucose tolerance test (OGTT) was given to all subjects and measurements were made of glycemia, insulinemia and the proportion of fatty acids in plasma phospholipids. Insulin resistance (IR) was estimated by homeostasis model assessment. Samples of cooking oil being used were obtained from the kitchens. The strength of association between variables was measured by calculating the odds ratio (OR) from logistic models, and the relationships were measured by linear correlation coefficients.

RESULTS

Insulin resistance was significantly less in people who used olive oil compared with those who used sunflower oil or a mixture. Statistical significance remained in the group of people with normal OGTT after adjusting for obesity. In the whole sample, IR correlated negatively with the concentration of oleic acid (r=-0.11; P=0.02) and positively with that of linoleic acid (r=0.10; P=0.02) from the cooking oil. In subjects with normal OGTT, IR correlated negatively with oleic acid from cooking oil (r=-0.17; P=0.004) and from plasma phospholipids (r=-0.11; P=0.01) and positively with the concentration of linoleic acid in cooking oil (r=0.18; P=0.004) and plasma phospholipids (r=0.12; P=0.005). The risk (OR) of having raised IR was significantly lower in people who consumed olive oil, either alone (OR=0.50) or mixed (OR=0.52) compared with those who consumed only sunflower oil.

CONCLUSION

There is an association between the intake of oleic acid, the composition of oleic acid in plasma phospholipids and peripheral insulin action.

Hypertension is related to the degradation of dietary frying oils

BACKGROUND

The family kitchen resembles an uncontrolled laboratory experiment, and some discrepancies in the relation between the risk of hypertension and dietary fat may be partly due to the manipulation to which the fats were subjected.

OBJECTIVE

We investigated whether deterioration in the quality of the cooking oils in the family household contributes to the risk of high blood pressure.

DESIGN

The study was cross-sectional. Anthropometric measurements were obtained for 1226 persons aged 18-65 y who were selected randomly from the municipal census of Pizarra, Spain. An oral-glucose-tolerance test was given to 1020 of these persons. Samples of the cooking oil being used were taken from the kitchens of a random subset of 538 persons. The concentrations of polar compounds and polymers were used as markers of the deterioration of the oils. The strength of association between variables was measured by calculating the odds ratio from logistic models.

RESULTS

Hypertension was strongly associated with obesity and was influenced by sex, diabetes, and age. The presence of excess polar compounds in the cooking oil and the use of sunflower oil were related to the risk of hypertension, whereas the concentration of monounsaturated fatty acids in the serum phospholipids was negatively related to this risk. These associations remained after inclusion in the models of age, sex, obesity, and the presence of carbohydrate metabolism disorder.

CONCLUSIONS

The risk of hypertension is positively and independently associated with the intake of cooking oil polar compounds and inversely related to blood concentrations of monounsaturated fatty acids.